1. Field of the Invention
This invention relates to the field of carriers for controlled release of scents, and in particular to a cylindrical or preferably tube-like scent body mounted in a tab-like carrier for deploying concentrated attractive insect pheromones, for example to be disposed in an insect trap.
2. Prior Art
Insect traps are known in which various compositions are used to attract the insects to the trap. The compositions may involve bait substances in which insects are drawn to a trap seeking food, or pheromones, to which the insects are drawn for purposes of reproduction. It is possible in connection with trapping boll weevils to combine pheromone attraction with food attraction by concentrating the boll weevils at preliminary plots of cotton. The insects are attracted to food at the trap plot, and the boll weevil aggregating pheromone encourages the insects into a trap.
Boll weevil traps are the subject of U.S. Pat. Nos. 3,949,515-Mitchell; 3,987,577-Hardee and 4,611,425-Dickerson. Traps of this type for use in the disclosed procedures have become standard equipment. Similarly, pheromone traps for gypsy moths are widely available as a common product.
Attractive artificially produced pheromones are known for various insects. These include, for example, the male attractive pheromone Grandlure for boll weevils, Dispar Lure for gypsy moths, Trimedlure for medflies, Gossyplure for pink boll worms and others. Pheromones are also available for oriental fruit moths and diamond back moths. Many other insects are subject to attractive pheromones, natural or artificial. The proclivities of the insects are used together with their instinctive response to pheromones for urging the insects into appropriate traps. For example, boll weevil traps are painted yellow, which is in itself attractive, and the insect's tendency to move geotropically upwardly into a collector is used to concentrate the insects in an enclosure at the top of the trap. A funnel shaped entrance is used so insects in the enclosure cannot readily find the exit. Tendencies of various insects are thus known and used, wherein insects are at least part concentrated using pheromones. The requirements in each case with pheromones are to locate the scent source in a trap and to broadcast the attractive pheromone scent to a wide area in which the insects are otherwise located.
Pheromones according to known techniques have been packed in laminated sheet-like sections with volatile scent-releasing material comprised in one or more laminate layers, and in cylindrical bodies or plugs in which the whole bodies are composed of scent releasing material. The tendency with any scent releasing substance is quite logically to employ a large surface area configuration in order to maximize the surface area exposed to air diffusing through the area. However, exposed scent-releasing surface area can present problems in the handling of pheromones. Some pheromones are effective attractive agents even at very low concentrations. Also, pheromones and their carriers can be toxic, particularly if taken orally or brought into contact with mucous membranes. These characteristics of insect pheromones make is undesirable to produce a pheromone lure in which the scented material is exposed on all available exterior surfaces, which could maximize dispersal. Persons handling the pheromones, particularly due to their high concentration at the source and low threshold effective concentration, must be careful to avoid contact, which also could result in various unintended lure locations, for example on outer surfaces of a trap.
A solid composition apt for entrapping scented chemicals such as insect pheromones is disclosed in commonly-owned patent applications Ser. No. 915,749 filed Oct. 6, 1986 and Ser. No. 053,609 filed May 20, 1987. This composition is useful for entrapping various chemicals in a solid body, providing for their sustained release. A functional group is entrapped in the lattice of a cross-linked hydrophobic polymer during the polymerization of the monomers forming the polymer lattice. This composition can entrap insect pheromones in the polymer, which results in a sustained pheromone-releasing solid. According to the present invention, such a composition can be packaged conveniently by in situ polymerization in a plastic tube. The pheromone is emitted at the ends, while the tube can be handled safely provided care is taken to avoid contact with the composition inside the tube. By controlling the dimension of the tube such as the length, diameter and relative proportion of the lumen of the tube occuppied by the pheromone-emitting solid composition, the rate of release of insect pheromone (or other scent) can be controlled. The tube can be supplied in a length from which single trap doses are cut, or the tube can be supplied in individual doses, for example with closed ends that are opened to commence broadcasting the pheromone. Enveloping a pheromone composition in a tube departs from the prior art tendency to maximize surface area, but has proved quite effective.
The packaging or mounting of insect attractive pheromones and other scented materials in a tube physically supports the pheromone or the like, and allows a user to have at least some protection from direct contact with the pheromone, namely by engaging the tube-and-pheromone packaged lure only by its sides remote from its two opposite ends. Handling of the tubes is not foolproof because the preferred tubes for holding the insect attractive pheromones and the like are normally quite small (e.g. 0.5-2.0 cm length and 0.3 cm diameter). Therefore, it can still be difficult to avoid contact with the pheromone material in the lure when handling the tubes. Use of pheromone lures requires certain manual steps, including installation of individual lures in insect traps and the like. One user may have a large number of traps to service. According to the present invention, a pheromone-carrying material such as a tube lure holding a pheromone-releasing composition is mounted on an additional carrier structure having a substantial marginal area for manipulation by the user. The carrier portion of the dispenser has certain structural features that retain the lure safely in position and allow appropriate air circulation adjacent the tube ends. The structural features likewise allow the user to conveniently install the carrier directly in certain known insect traps such as the standard Dickerson boll weevil trap. The attractive material is easily handled and safe from loss from exposed to the air for release of scent.
By facilitating the use of entrapped pheromone compositions, and by allowing technique for accurate sustained release without waste, the invention provides an efficient and practical means for handling and dealing with insect attractive pheromones.